Fire resistant pipe

Abstract

Fire resistant pipes and pipe fittings include a structural pipe wall formed from helically wound reinforcing fiber that is bonded together with a thermoset polymer resin selected from the group consisting of phenolic resins, siloxane-modified phenolic resins, furan resins, and mixtures thereof. In a first embodiment, a resin rich fire resistant layer is applied to the surface of the structural pipe wall. The carrier is capable of accommodating a large amount of resin. The resin used to impregnate the carrier is selected from the same group of resins used to form the structural pipe wall. It is desired that both resins be compatible, and preferably be the same, to facilitate forming a bond between the structural pipe wall and the fire resistant layer during cure. In a second embodiment, a number of energy absorbing material layers are disposed around the structural pipe wall, and are formed from a material capable of absorbing heat energy from a surrounding outside layer to produce a thermally insulating gas therebetween. A number of fiber-reinforced resin layers are disposed around the absorbing material layers. The fire resistant layer and energy absorbing material layers are formed having sufficient wall thickness to protect the structural wall from heat induced failure produced by exposing the outermost pipe wall to a 1,000 ° C. flame for at least five minutes in a dry condition.

What is claimed is: 
     
       1. A fire resistant pipe comprising: a structural wall comprising layers of helically wound reinforcing fiber bonded with a siloxane-modified phenolic resin; and   at least one fire resistant layer overlying the structural wall, wherein the fire resistant layer includes a fibrous carrier component impregnated with a siloxane-modified phenolic resin.   
     
     
       2. A fire resistant pipe as recited in claim 1 wherein the siloxane-modified phenolic resins selected to form the structural wall and the fire resistant layer are the same. 
     
     
       3. A fire resistant pipe as recited in claim 1 wherein the fire resistant layer comprises at least 75 percent by weight resin. 
     
     
       4. A fire resistant pipe as recited in claim 1 wherein the fiber component used to form the structural wall is selected from the group consisting of glass, carbon, and combinations thereof. 
     
     
       5. A fire resistant pipe as recited in claim 1 wherein the fibrous carrier component used to form the fire resistant layer is selected from the group consisting of glass containing mat, chopped glass containing mat, nylon containing mat, polyester containing mat, and combinations thereof. 
     
     
       6. A fire resistant pipe as recited in claim 1 wherein the helically wound reinforcing fiber comprises in the range of from 10 to 40 percent by weight resin. 
     
     
       7. A fire resistant pipe as recited in claim 1 wherein the fire resistant layer comprises in the range of from 75 to 95 percent by weight resin. 
     
     
       8. A fire resistant pipe comprising: a structural wall comprising layers of helically wound reinforcing fiber bonded with a phenolic resin; and   at least one fire resistant layer overlying the structural wall, wherein the fire resistant layer includes a fibrous carrier component impregnated with a phenolic resin, wherein the fire resistant layer comprises at least three times the resin content as the helically wound reinforcing fiber forming the structural wall.   
     
     
       9. A fire resistant pipe as recited in claim 1 wherein the siloxane-modified phenolic resin comprises: a phenolic resole resin;   a silicone intermediate; and   a sufficient amount of catalyst to effect cure.   
     
     
       10. A fire resistant pipe as recited in claim 9 wherein the siloxane-modified phenolic resin is prepared by using in the range of from 0.5 to 35 percent by weight silicone intermediate. 
     
     
       11. A fire resistant pipe comprising: a structural wall comprising layers of helically wound reinforcing fiber bonded with a resin selected from the group consisting of phenolic resins, siloxane-modified phenolic resins, furan resins, and mixtures thereof;   at least one fire resistant layer overlying the structural wall, wherein the fire resistant layer includes a fibrous carrier component impregnated with a resin selected from the group consisting of phenolic resins, siloxane-modified phenolic resins, furan resins, and mixtures thereof, and wherein the resin selected to form the fire resistant layer is compatible with the same as the resin selected to form the structural wall;   a number of energy absorbing material layers interposed between the structural wall and the fire resistant layer.   
     
     
       12. A fire resistant pipe as recited in claim 1 wherein the energy absorbing material layer is formed from polyethylene. 
     
     
       13. A fire resistant pipe comprising: a plurality of layers of helically wound reinforcing fiber bonded with a siloxane-containing thermoset polymer; and   at least one fire resistant layer overlying the helically wound layers comprising randomly oriented reinforcing fibers and substantially the same thermoset polymer as in the helically wound layers, wherein the polymer content of the fire resistant layer is 10 at least 75 percent by weight.   
     
     
       14. A fire resistant pipe comprising: a plurality of layers of helically wound reinforcing fiber bonded with a thermoset polymer selected from the group consisting of phenolic resins, siloxane-modified phenolic resins, furan resins, and mixtures thereof; and   at least one fire resistant layer overlying the helically wound layers comprising randomly oriented reinforcing fibers and substantially the same polymer as in the helically wound layers, wherein the polymer content of the fire resistant layer is at least 75 percent by weight, and wherein the fire resistant layer is sufficiently thick to withstand a 1,000° C. flame for at least five minutes in a dry conditioned without degrading the structural wall.   
     
     
       15. A fire resistant pipe comprising: a plurality of layers of helically wound reinforcing fiber bonded with a thermoset polymer selected from the group consisting of phenolic resins, siloxane-modified phenolic resins, furan resins, and mixtures thereof; and   at least one fire resistant layer overlying the helically wound layers comprising randomly oriented reinforcing fibers and substantially the same polymer as in the helically wound layers, wherein the polymer content of the fire resistant layer is at least 75 percent by weight, and wherein the thermoset polymer is a siloxane-modified phenolic resin prepared by combining:   a major proportion of phenolic resole or phenolic novolac resin;   a minor proportion of silicone intermediate; and   a sufficient amount of catalyst to facilitate processing and effect cure.   
     
     
       16. A fire resistant pipe as recited in claim 15 wherein the catalyst is selected from the group consisting of organometallic compounds, amine compounds, acids, bases, and mixtures thereof. 
     
     
       17. A fire resistant pipe as recited in claim 16 wherein the catalyst is a mixture of organometallic and amine catalyst. 
     
     
       18. A fire resistant pipe as recited in claim 13 wherein the carrier component used to form the fire resistant layer is selected from the group of materials consisting of glass fibers, nylon fibers, polyester fibers, carbon fibers, and combinations thereof. 
     
     
       19. A fire resistant pipe as recited in claim 13 wherein the fire resistant layer comprises in the range of from 75 to 90 percent by weight resin. 
     
     
       20. A fire resistant pipe as recited in claim 19 wherein the helically wound reinforcing fiber comprises in the range of from 10 to 40 percent by weight resin. 
     
     
       21. A fire resistant pipe comprising: a structural wall comprising layers of helically wound reinforcing fiber bonded with a resin selected from the group consisting of phenolic resins, siloxane-modified phenolic resins, furan resins, and mixtures thereof;   a number of energy absorbing material layers overlaying the structural wall, wherein the energy absorbing material is selected from the group consisting of materials capable of absorbing energy by phase transformation at a temperature below a degradation temperature of the structural wall; and   a number of fiber-reinforced resin layers disposed over an outside surface of the energy absorbing material layers, wherein resin component is selected from the same group of resins used to form the structural wall.   
     
     
       22. A fire resistant pipe as recited in claim 21 further comprising: a second number of energy absorbing material layers disposed over an outside surface of the fiber-reinforced resin layers, wherein the energy absorbing material used to form second number of energy absorbing material layers is selected from the group consisting of materials capable of absorbing energy by phase transformation at a temperature below a degradation temperature of the fiber-reinforced resin layers that are the same or different than that used to form the energy absorbing material layer overlaying the structural wall; and   a second number of fiber-reinforced resin layers disposed over an outside surface of the energy absorbing material layers.   
     
     
       23. A fire resistant pipe as recited in claim 21 further comprising a second number of energy absorbing material layers interposed between the first number of energy absorbing material layers and the fiber-reinforced resin layers, wherein energy absorbing material used to form the second energy absorbing material layers is different from that used to form the first number of energy absorbing material layers. 
     
     
       24. A fire resistant pipe as recited in claim 21 wherein the energy absorbing material layer is formed from polyethylene. 
     
     
       25. A fire resistant pipe as recited in claim 21 wherein the resin selected to form the structural wall is the same as the resin selected to form the fiber-reinforced resin layers. 
     
     
       26. A fire resistant pipe as recited in claim 25 wherein the resin is selected from the group consisting of phenolic resole resins and phenolic novolac resins. 
     
     
       27. A fire resistant pipe as recited in claim 25 wherein the resin is a siloxane-modified phenolic resin prepared by combining: a major proportion of phenolic resole or phenolic novolac resin;   a minor proportion of silicone intermediate; and   a sufficient amount of catalyst to facilitate processing and effect cure.